Study of Transient Current Distortion in CZT Detectors Based on Sentaurus TCAD

Under high-intensity gamma-ray irradiation conditions, the transient current distortion phenomenon of cadmium zinc telluride (CZT) detectors is closely related to the deep-level defects within the crystal. In this section, a response model for CZT detectors was established based on Sentaurus TCAD software. The transient currents of CZT detectors under different defect conditions were analyzed. Simultaneously, experimental verification of the relevant theoretical analysis results was conducted utilizing a steady-state radiation source device. Theoretical and experimental results indicate that under high-intensity gamma-ray irradiation conditions, the sharp peaks in the transient response current and the smoothness of the current curve in CZT detectors are influenced by the trapping and detrapping effects of charge carriers induced by deep-level defects within the crystal. The subbandgap illumination technique can mitigate the current distortion in the transient response for CZT detectors. This improvement is likely attributed to the increased capture cross-section of deep-level defects caused by the subbandgap illumination, thereby shortening the detrapping lifetime of deep-level defects and effectively suppressing the sharp peak phenomenon in the transient response. These findings will enhance our understanding of the mechanisms behind the current distortion in CZT detectors under high-intensity gamma-ray irradiation conditions and provide crucial theoretical support for the optimization and design of CZT detector performance in subsequent studies.